Anti-icing spinner construction

ABSTRACT

A spinner construction for maintaining ice accumulation thereon to an acceptably low level during operation of a gas turbine engine under icing conditions wherein a plurality of spaced fins extend from the arcuate outer surface of the spinner. The fins are sized and arranged relative to impinging water droplets so that ice formation occurs principally on the fins rather than the spinner arcuate outer surface.

United States Patent 1191 Campbell et a1.

ANTI-ICING SPINNER CONSTRUCTION Inventors: William B. Campbell; ArthurP,

Adamson, both of Cincinnati, Ohio Assignee: General Electric Company,Cincinnati, Ohio Filed: Oct. 4, 1971 Appl. No.: 186,074

US. Cl 416/201, 416/245, 415/143 Int. Cl. B64c 11/1 Field of Search...416/201, 245, 175, 203, 124, 416/94,177,176,198, 200;415/DIG. 1,121 A,143, 168

References Cited 7 UNlTED STATES PATENTS 9/1931 Grumpelt 4-16/175 [451Feb. 26, 1974 1,920,880 8/1933 Parker 416/175 2,260,786 10/1941Muhlenbruck 416/201 I 2,755,868 7/1956 Smith 416/245 X Quan 416/245 UXPrimary ExaminerEverette A. Powell, Jr.

Attorney, Agent, or Firm-James M. Kipling; Derek P.

Lawrence 5 7] ABSTRACT A spinner construction for maintaining iceaccumulation thereon to an acceptably low level during operation of agas turbine engine under icing conditions wherein a plurality of spacedfins extend from the arcuate outer surface of the spinner. The fins aresized and arranged relative to impinging water droplets so that iceformation occurs principally on the fins rather than the spinner arcuateouter surface.

7 Claims, 3 Drawing Figures ANTI-ICING SPINNER CONSTRUCTION Thisinvention relates to turbomachinery and, more.

particularly, to a spinner construction which mitigates ice build-up byenhancing the ice shedding characteristics of the spinner.

During aircraft flight through icing conditions, ice may accumulate onthe rotating spinner or bullet nose of the type used in aircraft gasturbine engines. In such applications, due to the high rotational speedof the spinner, if the spinner ice build-up is non-uniform it may causeexcessive engine vibration. On the other hand, if the ice build-up isshed in large pieces, it may cause damage to rotating or stationarycomponents of the turbomachine.

One method which has been heretofore frequently used to avoid excessiveice build-up on turbomachinery spinners involves heating the exposedspinner surfaces to a temperature such that ice accumulation isprevented or to a temperature sufficient to weaken the ice/spinner bondsuch that the ice is shed by centrifugal action before the ice build-upbecomes excessive. While such methods have been found effective inpreventing excessive accumulation, they generally require the propulsionsystem to provide electrical energy or hot air or gases which tend toreduce the propulsion systems efficiency and reliability whileincreasing its weight, complexity and initial and maintenance costs.

A primary object of the present invention is to provide a rotatingspinner construction which is geometrically configured such that icewill be automatically shed therefrom.

Another object of this invention is to provide a rotating spinnerconstruction for a gas turbine engine which is geometrically configuredso as to shed ice in the form of relatively small pieces.

Yet another object of this invention is a spinner construction whichreduces ice accumulation to an acceptably low level during operation ofa gas tubine engine under icing conditions.

Briefly, these and other objects, which will become apparent uponreading hereinafter, are achieved in the present invention by formingthe spinner with a plurality of fins or ribs which project generallyradially outwardly from the arcuate external surface of the spinner. Thefins are preferably sized and oriented on the spinner in relation to theimpinging airflow such that the fins shield or shadow the adjacentarcuate outer spinner surface from the impinging airflow. In thismanner, most or all of the water droplets carried by the air which wouldotherwise impinge on the spinner outer arcuate surface, impinge instaadon the fins. Where such impingement occurs during icing conditions, iceforms primarily on the fins where it is centrifuged off in small piecesbefore build-up becomes excessive.

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter of this invention, it isbelieved that the invention will be better understood upon reading thefollowing specification in conjunction with the accompanying drawings,wherein:

FIG. 1 is a partial perspective view of a gas turbing engine employingthe rotating spinner construction of this invention;

FIG. 2 is a partial plan view, drawn to an enlarged scale, taken alonglines 2-2 of FIG. 1; and

rality of radially extending blades 16 for pressurizing airflow throughthe duct 10.

The upstream end of the rotor 16 terminates in a bullet nose or spinner18 which is formed with an arcuate outer surface 20 which converges to anose at its upstream end 22.

,In order to mitigate ice build-up on the spinner 18 to an acceptablylow level during operation of the engine under icing conditions, and inaccordance with the present invention, the spinner is formed with aplurality of spaced fins or ribs 24 which extend generally radiallyoutwardly from the spinner outer surface 20.

Each fin 24 has been shown in FIG. 2 as being generally spiral-like inshape as it progresses from the upstream to the downstream end of thespinner such that the approaching air velocity, relative to the spinner,is at an incidence angle such that the portion of the spinner outersurface 20 between the fins 24 is shadowed from the impinging airflowand, hence, from the water droplets carried by the impinging air. Suchpreferred arrangement is diagrammatically shown in FIG. 3 wherein therelative direction of impinging air is indicated at 26, the resultantangle of attack relative to the spinner is indicated at 28, and theresultant ice build-up on the fins during icing conditions is indicatedat 30. The radial height of each fin 24 may be maintained constant overthe length of the fin or may be varied, depending upon number of finsemployed and the spacing of adjacent fins. For aerodynamic reasons,however, it is preferred that each fin 24 be of small radial heightrelative to the diameter of the spinner and that the angle of the fin atits downstream end, relative to the rotational axis 32 approximates theangle of the axially adjacent blades 16 as best shown in FIG. 2.

With the spinner geometry of this invention, it has been found that icewill shed from the fins 24 at a rate which maintains the total iceaccumulation on the spinner 18 to an acceptably low level and,additionally, that the ice is shed in small pieces which may be digestedby the fan 12 without damage. These improved ice sheddingcharacteristics, which have been observed in testing, are believed toresult from an increase in the stress levels of the ice/fin bond ascompared to the stresses that would be expected in the bond between aconventional spinner external surface and the ice formed thereon.

One factor that contributes to the improved ice sheddingcharacteristics'of the present spinner construction is that the finsurface area upon which ice formation will occur may be greatly reducedas compared to the spinner area upon which ice formation would occur inthe case of a conventional spinner.

Accordingly, assuming that ice will shed at the same build-up thicknessfor either the finned spinner of this invention or from a conventionalunfinned spinner of similar size and shape which is operating at thesame rotating speed, it will be apparent that the total mass of iceaccumulated on the reduced fin area will be less than that accumulatedon the larger ice forming area of the conventional spinner.

the ice, while in the conventional or unfinned spinner the bond issubjected primarily to tensile forces only.

While the fins 24 have been depicted and described as being generallyspiral in shape it will be understood that they may be circular orotherwise suitably shaped, it being important only that they be orientedrelative to the impinging water droplets so as to shield or shadow theadjacent spinner external surface therefrom.

From the foregoing, it will be apparent that the present inventionprovides improved spinner ice shedding characteristics while avoidingthe system disadvantages which attend spinnerheating arrangements.

While a particular embodiment of the present invention has been depictedand described, such is intended to be exemplary only and not definitiveand it will be understood by those skilled in the art that manymodifications, substitutions and changes may be made thereto withoutdeparting from the fundamental theme of the invention.

What is claimed is:

1. Means for improving the ice shedding characteristics of a rotatingspinner of the type used in gas turbine engines and having an arcuateexternal surface disposed within a circumscribing duct and, said meanscomprising a plurality of fins projecting generally radially from saidarcuate external surface, said fins being spaced, sized in radial heightand oriented relative to the spinner rotational axis such that liquiddroplets carried by air which would otherwise impinge on said arcuateexternal spinner surface in the area of said fins impinge instead ofsaid fins.

2. The structure of claim 1 further characterized in that said fins aregenerally spiral in shape.

3. The structure of claim 1 further characterized in that said fins aregenerally circular in shape.

4. In a fluid apparatus of the gas turbine engine type including arotating spinner disposed within a circumscribing duct and having anarcuate external surface upon which liquid droplets may be impingedunder icing conditions, means for improving the ice sheddingcharacteristics of said spinner comprising:

a plurality of spaced fins projecting generally radially from saidspinner external surface, with the radial height and spacing of saidfins being sized relative to the incidence angle of said impingingliquid droplets such that, in the area of said fins, liquid impingementand, hence, ice formation occurs primarily on said fins.

5. The structure of claim 4 further characterized in that said fins aregenerally spiral in shape.

6. The structure of claim 4 further characterized in that said fins aregenerally circular in shape.

7. The structure of claim 4 further characterized in that said fluidapparatus includes a circumferential row of blades adjacent thedownstream end of said spinner, said fins being generally spiral inshape and extending axially over a portion of said spinner externalsurface to its downstream end, said fins forming an angle relative tothe spinner rotational axis at said downstream end which isapproximately equal to the angle of said blades.

1. Means for improving the ice shedding characteristics of a rotatingspinner of the type used in gas turbine engines and having an arcuateexternal surface disposed within a circumscribing duct and, said meanscomprising a plurality of fins projecting generally radially from saidarcuate external surface, said fins being spaced, sized in radial heightand oriented relative to the spinner rotational axis such that liquiddroplets carried by air which would otherwise impinge on said arcuateexternal spinner surface in the area of said fins impinge instead ofsaid fins.
 2. The structure of claim 1 further characterized in thatsaid fins are generally spiral in shape.
 3. The structure of claim 1further characterized in that said fins are generally circular in shape.4. In a fluid apparatus of the gas turbine engine type including arotating spinner disposed within a circumscribing duct and having anarcuate external surface upon which liquid droplets may be impingedunder icing conditions, means for improving the ice sheddingcharacteristics of said spinner comprising: a plurality of spaced finsprojecting generally radially from said spinner external surface, withthe radial height and spacing of said fins being sized relative to theincidence angle of said impinging liquid droplets such that, in the areaof said fins, liquid impingement and, hence, ice formation occursprimarily on said fins.
 5. The structure of claim 4 furthercharacterized in that said fins are generally spiral in shape.
 6. Thestructure of claim 4 further characterized in that said fins aregenerally circular in shape.
 7. The structure of claim 4 furthercharacterized in that said fluid apparatus includes a circumferentialrow of blades adjacent the downstream end of said spinner, said finsbeing generally spiral in shape and extending axially over a portion ofsaid spinner external surface to its downstream end, said fins formingan angle relative to the spinner rotational axis at said downstream endwhich is approximately equal to the angle of said blades.